Latching relay



R. D. KEENAN LATCHING RELAY Sept. 25, 1962 Filed May 17, 1961 INVENTOR.

' Ralph D. Keenan Airy.

United States Patent 3,056,007 LATCHING RELAY Ralph D. Keenan, Park Ridge, 111., assignor to Automatic Electric Laboratories, Inc., Northlake, Ill., a corporation of Delaware Filed May 17, 1961, Ser. No. 110,736 Claims. (Cl. 200-104) This invention relates to relays, and more particularly to an arrangement for mechanically latching the armature of a relay in its operated position.

Previous designs of latching relays used a rather complex locking mechanism involving various arms and levers. In these prior constructions, it is noted that, for the most part, the relays were specifically designed for the particular latching arrangement. One previously known arrangement has a relatively straight latching spring held 'by a bracket which protrudes up from the frame of the relay, significantly increasing the height of the assembly. Furthermore, the mounting of the above mentioned bracket on the relay required the provision or addition of tapped holes. In addition, this straight latching spring does not always hold the armature tightly against the core after the relay is deenergized.

The present invention employs a latching spring which is secured in the contact spring pileup or one of the contact spring pileups-thus eliminating the need for special brackets or holes to mount the spring and facilitating ready addition of the latching feature to a conventional relay; the latching spring is designed to extend along the side of the relay frame and preferably along the slot between the armature backstop and the relay frame, so that there is no addition to either height or width of the relay; and furthermore, the spring is formed and pretensioned such that it positively prevents the armature from sagging away from the core after the relay is deenergized. A latching relay of the present embodiment may be employed, for example, in the control circuitry of vending machines or the like, where it is desired to terminate all service if a fault occurs, thus preventing erratic operation before a service man arrives.

-It is a primary object of this invention, therefore, to provide a latching mechanism for a relay which is appreciably simple and compact.

It is a feature of this invention to provide a latching spring secured in one spring pileup of a relay.

It is a further feature of this invention to provide a latching spring which extends along the slot between the relay frame and the armature backstop.

The invention will be more fully understood from the following detailed description of an embodiment there of. In the accompanying drawings:

FIG. '1 is a perspective view of a relay of the telephone type in the operated position with a latching spring shown in the left pileup of the relay as seen from the rear.

FIG. 2 is a perspective view of the latching spring showing the tongue which serves as a catch.

FIG. 3 is a top view of the relay in FIG. 1, showing the slot formed between the relay frame and the armature arm backstop which allows room for the latching spring.

FIG. 4 is a top view of the latching spring, the angle at which the spring is bent to fit the arm.

FIG. 5 is a cross-section of the latching spring taken along line 5-5 of FIG. 4, showing the tongue as being bent inwardly so as to form a notch for the armature arm.

Referring now to the drawings, the latching spring 11 is shown in FIGS. 1 and 3 as being secured in the left pileup 12 of relay by means of pileup mounting screws showing armature 8. It is noted that the left and right pileups are mirror images of each other and that a latching spring of the same general construction could also be used in the right pileup 13 with similar results. The contact springs in pileup 12 are shown cut away for convenience in explaining the action of spring 11, and a quick inspection of the drawing reveals that there is ample room for contact springs in this pileup and that arm 2 and buffer 14 are present for actuating the contact springs in this pileup.

In FIGS. 1 and 3, spring 11 is seen as being formed so that when it is mounted in pileup .12, it extends down into the slot 9 between the relay frame 7 and the armature backstop 15. In addition, spring 11 extends along the edge of frame 7 and at a slight angle therewith. At the end of spring 11, there is a U-shaped section (see FIGS. 2, 4, and 5) in which the outer end of the armature arm 2 moves. Spring 11 is bent so that the inside leg of this U-shaped section presses firmly against the arm 2 at all times. On this inside leg, a tongue 4 has been formed which is bent inwardly so that its upper end will serve as a notch or catch along the wall of the inside leg. The U-shaped portion of spring 11 is vertically positioned so that as relay 10 is actuated and the armature arm 2 moves from its unoperated position, the tapered side of tongue 4 allows arm 2 to move upward, however, when the relay is fully operated, and the armature has struck the core (not shown) of coil 6 and armature arm 2 has reached its maximum upward motion, the tip of tongue 4 slips under the bottom edge of arm- 2. In this manner, when relay 10 is deenergized, armature arm 2 is prevented from returning to the unactuated position; the configuration and tensioning of latching spring 11 insures that the spring pileups remain in their fully actuated position.

It is noted in FIGS. 2, 4 and 5 that the U-shaped section of spring 11 has an outer leg 3 which remains on the outside of arm 2 at all times. This leg serves as a surface against which manual pressure, if applied substantially perpendicular thereto, moves the end of spring 11 toward the relay frame 7, thus moving the end of tongue 4 from beneath arm 2. Arm 2 then returns to its unactuated position and the relay is again operable.

While the invention has been described with reference to a particular environment, other applications will be readily apparent to those skilled in the art. The invention, therefore, should not be limited to the particular arrangement shown and described but should cover all modifications, within the spirit and scope of the claims.

What is claimed:

1. In a mechanically latching relay of the type comprising a coil, a frame, at least one spring pileup secured near its rear end to said frame, and an armature pivotally mounted on said frame and having a portion engaging the front end of said spring pileup: a latching spring secured in said pileup and extending forwardly to a point adjacent the armature portion, and a catch on said spring urged by said spring against said portion so as to lock said armature when in its operated position.

2. A mechanically latching relay comprising: a coil, a frame, at least one spring pileup secured near its rear end to said frame, an armature pivotally mounted at the front end of said frame and having an arm extending rearwardly from said pivot along the side of said frame and engaging the front end of said spring pileup, a latching spring secured in said pileup and extending forwardly to a point adjacent said armature arm, and a catch on said spring urged by said spring against said arm so as to lock said armature when in its operated position.

3. A mechanically latching relay of the telephone type as claimed in claim 2 wherein said latching spring comprises: a relatively flat portion extending downwardly and along the side of said frame and terminating adjacent said armature arm, said catch being formed by the upper end of a tongue located near the forward end of said fiat portion and having a tapered side protruding therefrom, said armature arm being slidably engaged by said tapered side when said armature is in its unoperated position, such that upon actuation of said relay, said armature arm slides up said tapered side until the end of said tongue slips under the bottom of said arm to lock said arm in the actuated position.

4. A mechanically latching relay of the telephone type as claimed in claim 3 wherein: the end of said relatively flat portion of said spring forms one leg of a U-shaped portion, the legs of which embrace said armature arm on both sides thereof, so that, with the armature locked in the operated position, manual pressure exerted substantially perpendicular to the outside surface of the outer leg slides the end of said tongue from beneath said armature arm and allows said armature to return to its unoperated position.

5. A mechanically latching relay of the telephone type 20 comprising: a coil, a frame, at least one spring pileup 4 secured near its rear end to said frame, an armature having an arm terminating adjacent the front end of said spring pileup, said frame having, at its side near the rear, an L-shaped leg extending forwardly to a point beneath the rear end of said armature arm and so formed as to serve as a backstop for said armature arm, a latching spring secured in said pileup and extending forwardly be-' tween the side of said frame and said leg to a point adjacent the said arrnature arm, and a catch on said spring urged by said spring against said arm, so as to lock said armature when in its operated position.

References Cited in the file of this patent UNlTED STATES PATENTS 1,139,956 Craft May 18, 1915 2,617,906 Stehlik Nov. 1 1, 1952 FOREIGN PATENTS 1,027,795 Germany Apr. 10, 1958 

